CPT Coding Interview Questions
Common Questions and Answers
Q: What is the difference between CPT and ICD-10-CM?
A: CPT codes describe procedures and services performed (WHAT was done) and are used primarily in outpatient and physician office settings. ICD-10-CM codes describe diagnoses (WHY the patient was seen) and are used in all healthcare settings. Both are required on most claims — CPT tells the payer what was done, ICD-10-CM supports medical necessity.
Q: What is modifier -25 and when is it used?
A: Modifier -25 is appended to an Evaluation and Management service code when a significant, separately identifiable E&M was performed on the same day as a procedure. For example, a patient presents with a skin lesion to be removed, but also has a new complaint (chest pain) that requires its own history, exam, and medical decision making. The E&M gets -25, the removal code stands alone. Documentation must support that the E&M was above and beyond the pre/post-operative care of the procedure.
Q: What is the global surgical package?
A: The global surgical package bundles the pre-operative visit (day before or day of surgery), the surgical procedure, and all post-operative follow-up care within the global period (0, 10, or 90 days). You cannot bill separately for routine post-op visits, dressing changes, or suture removal within the global period. Return to OR for complications uses modifier -78.
Q: How do you code multiple procedures in the same session?
A: List codes in descending order of value (highest RVU first). Append modifier -51 to the second and subsequent procedures to indicate multiple procedures. The primary procedure pays 100%, the second pays 50%, additional procedures pay 25% under Medicare reimbursement rules. Add-on codes and modifier-51 exempt codes do not follow this rule.
Q: What are Category III codes and when do you use them?
A: Category III codes are temporary codes for new and emerging technology, services, and procedures. They are 4 digits + T (e.g., 0054T). Use them instead of unlisted codes when a Category III code exists for the service performed. They do not have RVU values and payer coverage varies. They help the AMA track utilization to potentially promote the technology to Category I.
Q: What is the difference between a new and established patient?
A: A new patient has not received any professional service from the physician, or another physician of the same specialty and subspecialty who belongs to the same group practice, within the past three years. An established patient has received such a service within three years. When physicians cover for each other, the patient may be considered established to the covering physician.
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